class Solution:

    def climbStairs(self, n: int) -> int:
        dp = []
        dp.append(1)
        dp.append(1)
        result = 0
        i = 2
        while (i <= n):
            result += dp[i - 1] + dp[i - 2]
            dp.append(result)
            i += 1
            result = 0
        return dp[i - 1]